Distributed Estimation Method Of Urban Water Resource Dissipation Based On Remote Sensing

With the acceleration of urbanization,urban population,area and scale continue expanding and the evapotranspiration of urban water resource increases significantly.The related study is hard due to the lack of observation and the urban evapotranspiration is only estimated through indirect methods.This research considering the difference of social water consumption and natural consumption,estimated the distributed urban evapotranspiration through Landsat remote sensing image data,according to the relationship between land use and water consumption.Tianjin New Coastal District(TNCD)was selected for application.The main results are as follows:(1)By using the Landsat remote sensing image data and combining the threshold segmentation method with visual interpretation,the identification method of artificial shoreline and urban scope of coastal city under the influence of tidal flat development was proposed.This method was used to identify the land use of land area and tidal flat in TNCD from 2002 to 2018.According to the high-resolution Google satellite remote sensing image,the construction land of TNCD was divided into 7 categories.Reverse updating method was used to visually interpret the fine classification results of construction land.(2)According to the water use index method of different types of land and the refined identification results of urban construction land,an estimation method of social and economic water consumption based on urban construction land was established.This method was used to estimate the socio-economic water consumption and its spatial and industrial distribution in TNCD from 2002 to 2018.From 2002 to 2018,the average proportion of urban industrial water consumption,urban residents' water consumption,urban public water consumption and urban mixed water consumption in TNCD for many years is 59.4%,14.2%,12.8% and 13.6%.Industrial water consumption is the main social and economic water consumption in TNCD.The total water consumption keep increasing,mainly distributed along the Haihe River.The average water consumption intensity is about 732.9mm.(3)Based on the SEBAL model of land surface heat balance and Landsat remote sensing image data from 2002 to 2018,the natural evapotranspiration of TNCD was estimated.The temporal and spatial distribution characteristics of natural evapotranspiration are analyzed.The P-M formula was used to analyze and verity the rationality of the estimation results.The daily evapotranspiration of the five images was3.7mm?6.2mm.The evapotranspiration of different land use types is different,and the evapotranspiration of water area is larger.Combined with the results of land use classification,the spatial and temporal distribution characteristics of natural evapotranspiration under different land use conditions were analyzed.The average error of P-M formula was 12.42% compared with the model simulation results,which met the accuracy requirements.This study enriches the mechanism of urban water resource evapotranspiration.As the same time,it improves the estimation method of urban water resource evapotranspiration and its temporal and spatial distribution,which has important practical significance for urban water resource management.